Polarization mode dispersion, called PMD, has an adverse effect on high-speed optical data transmission. The Proceedings of the Optical Fiber Communication Conference OFC2001, Mar. 17-22, 2001, Anaheim, Calif., USA, Presentation PD27 disclosed a method for measurement of polarization mode dispersion in which a polarization scrambler is used which can produce a large number of output polarizations, or all possible output polarizations, from a specific input polarization. The output polarizations which can be produced define a three-dimensional, not only flat figure, within the Poincaré sphere. Further polarization scramblers are described in Electronics Letters, Volume 30 (1994)18, pages 1500-1501. These can produce a depolarized output signal from any desired input polarizations. At least for certain input polarizations, the output polarizations which are produced define, however, only a flat figure, and not a three-dimensional figure, within the Poincaré sphere, since depolarization is a necessary precondition, but not in itself a sufficient precondition, for output polarizations to actually be produced which define a three-dimensional figure, and not just a flat figure, within the Poincaré sphere.
Furthermore, ideally, the output polarizations which are produced should be uncorrelated; that is to say, the correlation matrix of the normalized Stokes vectors of the output polarization should be equal to ⅓ times the 3×3 unit matrix.
An object of the present invention is, thus, to specify a polarization scrambler, as well as an associated method for polarization scrambling, which emits uncorrelated output polarizations for any given input polarizations.